Hi there, i think i can solve your problem. i may need access to the source code and the logs. Seems that the script that fetch the images crashes or not connect corectly.
It may take from 30min to 6 hours to fix this bug.
A few words about me: I am an certified web programmer in HTML, CSS, PHP, MySQL and JavaScript. I also have very good knowledge of wordpress, opencart and phpbb. I have an experience of over 7 years, during which I worked for many web agencies.